Using Google Trends, researchers analyzed the Google search query volumes from 2004 to 2011 for a set of 98 mostly finance-related search terms, looked at how stock prices changed over that same time, and tried to see if they could retroactively tease out search patterns that showed “early warning signs” of market moves. They also tested trading strategies that would act on these signs.

The volume of the search term “debt” turned out to be the word that showed the most promise, and one trading plan based on changes in searches for this term would have yielded a return of 326 percent over the period analyzed, the authors found. For comparison, a “buy and hold” investment in the Dow Jones Industrial Average yielded 16 percent return.”